Method of making hollow sheet-metal structures.



L. L. KNOX.

METHOD 0F MAKING HOLLOW SHEET METAL STRUCTURES.

APPLICATION FILED NOV.12. 1915.

Patented June 13,

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INVEN'TOR WITNESSES LUTHER L. KNOX, OF

MONTGOMERY MURRAY METHOD OF MAKING HOLLOW AVALON, PENNSYLVANIA, ASSIGNOR OF AND ONE-THIRD TO JOHN S. CRAIG.

specification of Letters Patent.

oNE-THiRn- To SHEET-METAL s'raUc'rUaEs.4

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Application led November` 12, 1915. Serial No. 61,092.

T0 all whom it may concern:

Be it known that I, LUTHER L.fKNox, a citizen of the United States, residing at Avalon, in the county of Allegheny and State of Pennsylvania, have invented a new and useful Method of Making Hollow Sheet- Metal Structures, of which the following is a full, clear, and exact description, reference being had to the accompanying drawings, forming partof this specification, in which- Figures 1, 2, 3, 4 and 5 are sectional views largely diagrammatic showing different steps in the manufacture of a twyer; and Fig. 6 is a sectionalview of the finished twyer.

My invention has relation to the manufacture of hollow sheet metal structures, such as twyers; and is designed to provide a simple and efficient method by which such a structure may be formed from a single piece of sheet metal.

The nature of my invention will be best understood by reference to the accompanying drawings, in which I have illustrated my preferred form of twyer, together with the method of manufacturing the same.

Inaccordance with my invention, I provide a suitable sheet metal blank 2, of plate form, such as shown in section in Fig. 1, and by a series of drawing and shaping operations form therefrom a cylindrical body 3, closed at one end and yopen at the other. The successive shaping operations are of a nature to reduce the diameter of the cylindrical body while increasing its length, as indicated in Figs. 2 and 3. When the body has lbeen thus formed to the required length and diameter, it is placed over a suitable former or anvil 4, in inverted position, and by means of a plunger, the closed bottom portion of the body is forced downwardly within the body in the manner illustrated in Fig. 4. The inner portion 5,- which is thus forced downwardly within the anvil or former is made somewhat longer than the outer body portion 6. The structure as thus formed is then removed from the anvil or former and the closed .end 7 of the portion 5 is cut out. The mouth part of the portion 6 is then expanded, as indicated at 8 in Fig. 5,- and the portion 6 is also fiared outwardly, as shown in said figure. The inlier portion 5 is also similarly flared. The projecting portion 5a of the portion 5 is then wardly within the body,

bent downwardly and outwardly to close the space between the inner and outer walls of the structure, and the free edges thereof are welded to the upper edge of the portion 8. The portion 5fL is also perforated and suitable sleeves or bosses 9 and 10 are welded or otherwise secured 4in these perforations, to provi-de for water-circulating connection. The boss 9 may have secured therein a discharge pipe 11, which extends to a point near the inner, end of the structure.

My invention provides a sheet metal twyer whose body is formed from a single piece of metal and in which the only seam is the welded joint between the outer edge of the portion 5a and the portion 8. The method of manufacture described is a simple and comparatively inexpensive one and capable of being readily carried out on a commercial scale.

It will be apparent that can be made in the precise form and shape of the finished article, as well as in the method of manufacture thereof', without departing from the spirit and scope of my invention as defined in the appended claims.

I claim:

l. The herein described method of making hollow double wall sheet metall structures, which consists in shaping `a 'sheet metal blank into an approximately cylindrical body closed at one end, then forcing a portion of said body from its closed end inand expanding the inner and outer walls of the structure to frusto-conical form, substantially as described.

2. The herein-described method of making hollow double wall sheet metal struc-4 tures, which consists in shaping a sheet metal blank into an approximately cylindrical body closed at one end, then forcing a portion of said body from its closed end inwardly within and through the body in the reverse direction, and bendingand stretching a portion of the said closed end portion over and outwardly to form a closure for the open end of the structure, substantially as described. Y

3. The herein described method of making hollow twyer structures, which consists in shaping a sheet metal blank into an approximately cylindrical body closed at one end and open at the other end, then forcing a portion of the body from the closed en various changesA thereof inwardly within the body, and thenv utilizing a part of such portion to form a closure for the structure, substantially/ as described.

4. The herein described method of forming hollow twyer structures, which consists in providing a cylindrical sheet metal bodV closed at one end and open at the other end, thentforcing a portion of such body from the closed end thereof inwardly within the body to formeJ double wall structure, and utilizing apart of saidv portion to form a closure between the inner and outer walls of the structure at the substantially es described.

5. The herein described method of formopen end thereof,

ing twyer structures, which consists in providing a cylindrical sheet metal structure closed at one end and open at the other end, forcing a portion of said structure inwardly within the body ofthe structure to thereby form an inner wall thereof, then shaping the inner and outer walls to the desired form, and finally utilizing a projecting portion of the inner wall to form a closurecbetween the two walls, substantially. as described.

In testimony whereof, 'I have hereunto set my hand. i

i LUTHER L. KNOX. Witnesses:

"Gno, H. PARMELEE, H.- M. CORWIN. 

